Pistols blazing, Kazmierczak left the stage and walked up one one aisle toward the back of the auditorium, then across the room and down the other aisle, said Larry Trent, director of the Illinois State Police. Kazmierczak then went back up onstage and killed himself, Trent said.

Since the shootings, the campus has been almost deserted. On Friday, a few students placed flowers at crosses that had been planted in the snow and wondered whether they would ever be able to regain a sense of security.

“It does make you scared to go to school,” said Allison Warren, 20, of the Quad Cities. “I’m going to be looking over my shoulder and skeptical of people coming into class late.”